Catalyst for fluidized bed ammoxidation reaction, and method for producing acrylonitrile

Abstract

A catalyst for a fluidized bed ammoxidation reaction containing silica and a metal oxide, wherein a composite of the silica and the metal oxide is represented by the following formula (1). Mo 12 Bi a Fe b Ni c Mg d Co e Ce f Cr g Zn h X i O j /(SiO 2 ) A   (1) (in formula (1), X is selected from the group consisting of K, Rb, and Cs, a, b, c, d, e, f, g, h, and i, each satisfy 0.1≤a≤1, 0.5≤b≤4, 0.5≤c≤6.5, 0.2≤d≤2.5, 0.5≤e≤7, 0.2≤f≤1.2, g≤0.05, n≤4, and 0.05≤i≤1, A represents a content of silica (% by mass) in the composite and satisfies 35≤A≤48, and values of α, β, and γ calculated by the following expressions (2), (3), and (4) satisfy 0.03≤α≤0.12, 0.1≤β≤0.7, and 0.2≤γ≤4.) α=1.5a/(1.5(b+g)+c+d+e+h)   (2) β=1.5(b+g)/(c+d+e+h)   (3) γ=e/(c+d+h)   (4)

1 . A catalyst for a fluidized bed ammoxidation reaction comprising:
 silica and   a metal oxide, wherein   a composite of the silica and the metal oxide is represented by the following formula (1):
   Mo 12 Bi a Fe b Ni c Mg d Co e Ce f Cr g Zn h X i O j /(SiO 2 ) A    (1);
 
   wherein Mo represents molybdenum, Bi represents bismuth, Fe represents iron, Ni represents nickel, Mg represents magnesium, Co represents cobalt, Ce represents cerium, Cr represents chromium, Zn represents zinc, X represents at least one element selected from the group consisting of potassium, rubidium, and cesium, SiO 2  represents silica, a, b, c, d, e, f, g, h, i, and j each represent an atomic ratio of each element and satisfy 0.1≤a≤1, 0.5≤b≤4, 0.5≤c≤6.5, 0.2≤d≤2.5, 0.5≤e≤7, 0.2≤f≤1.2, g≤0.05, h≤4, and 0.05≤i≤1, provided that j represents an atomic ratio of an oxygen atom, the atomic ratio satisfying valences of constituent elements excluding silica, A represents a content of silica (% by mass) in the composite and satisfies 35≤A≤48, and values of α, β, and γ calculated from the atomic ratios of respective elements by the following expressions (2), (3), and (4) satisfy 0.03≤α≤0.12, 0.1≤β≤0.7, and 0.2≤γ≤4:
   α=1.5 a /(1.5( b+g )+ c+d+e+h )   (2);
 
   β=1.5( b+g )/( c+d+e+h )   (3); and
 
   γ= e /( c+d+h )   (4).
 
   
     
     
         2 . The catalyst for the fluidized bed ammoxidation reaction according to  claim 1 , wherein δ calculated from the atomic ratio of each element by the following expression (5) satisfies
   δ=12−1.5( a+b+f+g )− c−d−e−h    (5).
 
 
     
     
         3 . The catalyst for the fluidized bed ammoxidation reaction according to  claim 1 , wherein the X represents rubidium. 
     
     
         4 . The catalyst for the fluidized bed ammoxidation reaction according to  claim 1 , wherein ε calculated from the atomic ratio of each element by the following expression (6) satisfies 0.5≤ε≤3.0:
   ε=f/a   (6).
 
 
     
     
         5 . A method for producing the catalyst for the fluidized bed ammoxidation reaction according to  claim 1 , the method comprising:
 a first step of preparing a starting material slurry;   a second step of obtaining a dried particle by spray-drying the starting material slurry; and   a third step of calcining the dried particle, wherein a silica sol, which has an average particle diameter of primary particles of 5 nm or more and less than 50 nm and has a standard deviation of less than 30% based on the average particle diameter in a particle size distribution of the primary particles, is used as a starting material for the silica in the first step.   
     
     
         6 . A method for producing acrylonitrile using the catalyst for the fluidized bed ammoxidation reaction according to  claim 1 .